It is frequently necessary to transmit a signal between a pair of co-acting members, at least one of which may be moving or may be stationary relative to the other. This situation arises most frequently in structures wherein one of the members is rotatable relative to the other; so that the signal must be transmitted during rotating conditions and/or during stationary conditions.
There have been many attempts to solve this problem of signal transmission; but most of them have been unsatisfactory, for a variety of reasons -- including cost, reliability, maintenance, short life-times, environment, etc.
The disclosed invention overcomes the disadvantages of the prior art systems in an economical manner that provide dependability, long life, freedom from spurious effects, maintenance, etc.